The emergence of mobile application raises the challenge of data exchange between entities. In the scope of data exchange, confidentiality, integrity and availability of data is an important issue. Public Key Infrastructure (PKI) provides mechanisms for ensuring integrity (e.g. data signature) and confidentiality mechanisms (e.g. session key).
A. Shamir “Identity-based cryptosystems and signature schemes” introduced the concept of identity-based cryptography (IBC) using RSA function. RSA is based on public-private key pair cryptography mechanisms. The idea of IBC is to exploit user's identity as a public key. User's identity is information related to the user such as user's name, snail or email address.
RFC 2898 describes password-based cryptography.
C. Gentry, A. Silverberg “Hierarchical ID-based Cryptography” describes identity-based cryptography and hierarchical identity-based cryptography. Here, the identity or the hierarchical identity of the users is taken into account for generating a key pair for secure transmission.
G. Koien, V. Oleshuk “Location Privacy for cellular systems” describes another example of identity-based cryptography. Identity (e.g. bob@operator.net) is used as public key and the Private Key Generator generates a private key accordingly.